Frequently asked questions

Yes. They work best in direct sun but still make some electricity on cloudy days. See are solar panels worth it?.

The Energy Saving Trust puts a typical home system at about 4.5 kWp and about £7,600. Government figures give a median of £1,595 per kW for systems up to 4 kW in 2025/26 (installation and VAT included, batteries not). See costs.

The Energy Saving Trust estimates 9–12 years for a typical system, including export payments, depending on where you live and how much you’re at home (July 2026 prices). Try our savings estimator.

For a south-facing roof at 35°, MCS figures range from about 736 to 1,130 kWh per kWp a year, depending on your MCS postcode zone — lowest in Lerwick, highest in the Brighton zone. See how much will solar save me?.

Expect about 80% of what a south-facing roof would make at a typical pitch. A flat installation gives about 84% (MCS data).

Usually not for rooftop panels on a house, within size limits. The main exceptions are listed buildings and some installations in conservation areas or World Heritage Sites. Rules differ in each nation — check with your council. See planning permission.

Not when they’re installed in a home: 0% until 31 March 2027, and batteries have been included since 1 February 2024. Kits bought from a shop without installation are charged standard-rate VAT. See VAT on solar.

It requires larger suppliers in Great Britain to pay you for electricity you export. You need an MCS (or equivalent) certificate and a smart meter that records exports. See the Smart Export Guarantee.

On 9 October 2026, examples included Outgoing Octopus at 12p per kWh, E.ON Next Export Exclusive at 13p (for E.ON Next customers) and EDF’s SEG Export Variable at 3p (open to anyone). Rates change often.

It depends. MCS figures show a battery can roughly double or triple how much of your solar you use yourself, but the Energy Saving Trust says the savings alone may not justify the cost — about £4,600 for 5 kWh. See batteries.

Panels 25 years or more, inverters about 12 years and batteries about 10–12 years, according to the Energy Saving Trust.

Yes if you want Smart Export Guarantee payments or a Warm Homes Loan — and it’s strongly advised anyway. See MCS certification.

At least three. Don’t pay more than 25% as a deposit. Use our quotes checklist.

Complain to the installer first, then to MCS. MCS can refer eligible disputes to a free ombudsman whose decision is binding on installers certified to its new scheme. See MCS certification.

There’s no general solar grant. Lower-income households may get help through the Warm Homes Plan, ECO4 (until 31 December 2026), Warm Homes Nest in Wales or schemes in Scotland, and reduced-rate loans are available through the Warm Homes Loan Scheme. See grants and loans.

Possibly a plug-in kit of up to 800 W, with your landlord’s or freeholder’s permission — legal in Great Britain since 27 August 2026. See solar for renters and flats.

Not normally, because plug-in kits don’t have an MCS certificate. See plug-in solar.

Yes. Your installer notifies or applies to the network operator under the G98 or G99 rules. You must register a plug-in kit yourself before using it.

Rarely. In the UK, rain keeps panels clean if they’re tilted at 15° or more. Keep nearby trees trimmed. See maintenance and cleaning.

It could be. Trading Standards has warned about fake “faulty inverter” and “mis-selling compensation” calls. Don’t give details over the phone; contact your original installer, or the Citizens Advice consumer service on 0808 223 1133. See scams.

Most mortgage lenders must agree to a lease of your roof space. In Northern Ireland, lenders don’t accept roof-space leases.

Yes. There’s no Smart Export Guarantee, plug-in solar isn’t yet legal, the planning rules differ and VAT on electricity stays at 5%. See Scotland, Wales and Northern Ireland.